This is how I see this phenomenon...Ribosomes attach to mRNA because large and small ribosomal subunits are 'flooding' the cytosol, so the 'finding of an mRNA' is not an actual finding but more like a fortuite collision between the mRNA and the small ribosomal subunit, with a critical 5'-cap and PolyA participation in that initial interaction and potentially consolidating the interaction. Subsequently, a coordinated sequence of event involving many auxiliary factors (e.g. eLF3, tRNA-met, other elF) collaborate in this association/interaction , scanning and final assembly of a functional translation machinery.

So basically...most molecular interactions that took place inside cells actually happen in a soup 1000s other molecules, so extremely coordinated events are product of collisions, many of them unproductive or suboptimal, however some how nature has managed enhance these interactions but various means...high relative concentrations, specific recognition sites and so that improved the odds. In some cases the interacting molecules are compartmentalised, tethered to a particular spot and restricted to a site inside the cell that increase their relative concentrations and may, in some cases, put them close to their interaction partners. The later, for instance, is very common in signalling pathways where their intracellular effectors are tethered to the plasma membrane (for example) where extacellular signal receptors happen to be located, this, in turn puts them relatively close to each other aiding a functional collisions (interactions) and you can imagine what happen afterwards.

I hope this helps!

This is how I see this phenomenon...Ribosomes attach to mRNA because large and small ribosomal subunits are 'flooding' the cytosol, so the 'finding of an mRNA' is not an actual finding but more like a fortuite collision between the mRNA and the small ribosomal subunit, with a critical 5'-cap and PolyA participation in that initial interaction and potentially consolidating the interaction. Subsequently, a coordinated sequence of event involving many auxiliary factors (e.g. eLF3, tRNA-met, other elF) collaborate in this association/interaction , scanning and final assembly of a functional translation machinery.

So basically...most molecular interactions that took place inside cells actually happen in a soup 1000s other molecules, so extremely coordinated events are product of collisions, many of them unproductive or suboptimal, however some how nature has managed enhance these interactions but various means...high relative concentrations, specific recognition sites and so that improved the odds. In some cases the interacting molecules are compartmentalised, tethered to a particular spot and restricted to a site inside the cell that increase their relative concentrations and may, in some cases, put them close to their interaction partners. The later, for instance, is very common in signalling pathways where their intracellular effectors are tethered to the plasma membrane (for example) where extacellular signal receptors happen to be located, this, in turn puts them relatively close to each other aiding a functional collisions (interactions) and you can imagine what happen afterwards.

I hope this helps!

Generally a m-RNA after post transcriptional modification attaches to the the floating ribosome in the cytosol. The m-RNA is short lived and if it fails to attach itself to the ribosome by chance, it gets digested in the cytosol